Synthesis and Characterization of Multifunctional Nanovesicles Composed of POPC Lipid Molecules for Nuclear Imaging

The integration of nuclear imaging analysis with nanomedicine has tremendously grown and represents a valid and powerful tool for the development and clinical translation of drug delivery systems. Among the various types of nanostructures used as drug carriers, nanovesicles represent intriguing platforms due to their capability to entrap both lipophilic and hydrophilic agents, and their well-known biocompatibility and biodegradability. In this respect, here we present the development of a labelling procedure of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine)-based liposomes incorporating an ad hoc designed lipophilic NOTA (1,4,7-triazacyclononane-1,4,7-triacetic acid) analogue, derivatized with an oleic acid residue, able to bind the positron emitter gallium-68(III). Based on POPC features, the optimal conditions for liposome labelling were studied with the aim of optimizing the Ga(III) incorporation and obtaining a significant radiochemical yield. The data presented in this work demonstrate the feasibility of the labelling procedure on POPC liposomes co-formulated with the ad hoc designed NOTA analogue. We thus provided a critical insight into the practical aspects of the development of vesicles for theranostic approaches, which in principle can be extended to other nanosystems exploiting a variety of bioconjugation protocols.

44Ti diffusion labelling of commercially available, engineered TiO2 and SiO2 nanoparticles

In realistic exposure scenarios, the detection and quantification of engineered nanoparticles in complex environmental or biological matrixes is a challenge since nanoparticle concentrations are frequently low and have to be discerned from a background that may contain the same elements in various chemical forms in much higher concentrations. The use of radiolabelled nanoparticles may overcome these difficulties offering high detection sensitivity without the necessity of complex sample preparation procedures. However, the labelling procedure must not alter the physicochemical and biological properties of the nanoparticles. In the present work, the radiolabelling of three different types of TiO2 nanoparticles with primary particle sizes between 5 nm and 26 nm with commercially available 44Ti has been investigated applying a simple diffusion heat treatment at 180 °C for 2.5 h on nanoparticles impregnated with a solution containing the 44Ti radiolabel. The same treatment has been investigated to radiolabel amorphous SiO2 nanoparticles with 44Ti. The radiolabels are stably integrated in the nanoparticle matrix, and the release is less than 0.1% in aqueous suspension at neutral pH for at least 4 weeks. The method appears to be fast and reliable. By transmission electron microscopy, dynamic light scattering and ζ-potential measurements, only minor alterations of the nanoparticle size could be detected in the range of 1 to 2 nm.

Toxicity and Functional Impairment in Human Adipose Tissue-Derived Stromal Cells (hASCs) Following Long-Term Exposure to Very Small Iron Oxide Particles (VSOPs)

Magnetic nanoparticles (NPs), such as very small iron oxide NPs (VSOPs) can be used for targeted drug delivery, cancer treatment or tissue engineering. Another important field of application is the labelling of mesenchymal stem cells to allow in vivo tracking and visualization of transplanted cells using magnetic resonance imaging (MRI). For these NPs, however, various toxic effects, as well as functional impairment of the exposed cells, are described. The present study evaluates the influence of VSOPs on the multilineage differentiation ability and cytokine secretion of human adipose tissue derived stromal cells (hASCs) after long-term exposure. Human ASCs were labelled with VSOPs, and the efficacy of the labelling was documented over 4 weeks in vitro cultivation of the labelled cells. Unlabelled hASCs served as negative controls. Four weeks after labelling, adipogenic and osteogenic differentiation was histologically evaluated and quantified by polymerase chain reaction (PCR). Changes in gene expression of IL-6, IL-8, VEGF and caspase 3 were determined over 4 weeks. Four weeks after the labelling procedure, labelled and unlabelled hASCs did not differ in the gene expression of IL-6, IL-8, VEGF and caspase 3. Furthermore, the labelling procedure had no influence on the multidifferentiation ability of hASC. The percentage of labelled cells decreased during in vitro expansion over 4 weeks. Labelling with VSOPs and long-term intracellular disposition probably have no influence on the physiological functions of hASCs. This could be important for the future in vivo use of iron oxide NPs.

Comparison of Different Methods to Determine the DNA Sequence Preference of Ionising Radiation-Induced DNA Damage

Ionising radiation (IR) is known to induce a wide variety of lesions in DNA. In this review, we compared three different techniques that examined the DNA sequence preference of IR-induced DNA damage at nucleotide resolution. These three techniques were: the linear amplification/polymerase stop assay, the end-labelling procedure, and Illumina next-generation genome-wide sequencing. The DNA sequence preference of IR-induced DNA damage was compared in purified DNA sequences including human genomic DNA. It was found that the DNA sequence preference of IR-induced DNA damage identified by the end-labelling procedure (that mainly detected single-strand breaks) and Illumina next-generation genome-wide sequencing (that mainly detected double-strand breaks) was at C nucleotides, while the linear amplification/polymerase stop assay (that mainly detected base damage) was at G nucleotides. A consensus sequence at the IR-induced DNA damage was found to be 5′-AGGC*C for the end-labelling technique, 5′-GGC*MH (where * is the cleavage site, M is A or C, H is any nucleotide except G) for the genome-wide technique, and 5′-GG* for the linear amplification/polymerase stop procedure. These three different approaches are important because they provide a deeper insight into the mechanism of action of IR-induced DNA damage.

Ethanol effects on 68Ga-radiolabelling efficacy and radiolysis in automated synthesis utilizing NaCl post-processing

Objective Recent studies showed that ethanol in the reaction mixture improves radiolabelling with trivalent radiometals in terms of precursor amount, reaction time, reaction temperature and radiolysis. With regard to clinical application, this effect is of practical interest in radiopharmacy. The aim of this study was to evaluate whether the positive effect of ethanol can be exploited in automated systems utilizing NaCl-post processing. Methods Gallium-68 was obtained from a 1.85 GBq 68Ge/68Ga-generator. Radiolabelling was performed on an automated 68Ga-labelling cassette module. The standard labelling protocol was used without modifications. 0–40 vol% ethanol were added to the reaction mixture. Quality control was performed using radioHPLC and radioTLC. Results Utilization of additional ethanol on an automated cassette module can be achieved by adding ethanol directly to the buffer solution without further modifications of the standard procedure. Radiolysis was decreased significantly as analysed by radioHPLC. Conclusion It was possible to combine the positive effects of ethanol on radiolabelling efficacy and radiolysis with the standard labelling procedure of an automated cassette module system. The whole process guarantees safe preparation of highly pure 68Ga-peptide for clinical application.

Fluorescent labelling of boar spermatozoa for quantitative studies on competitive sperm–oviduct binding

Invitro sperm–oviduct binding assays enable assessment of the capacity of spermatozoa to form a ‘reservoir’ in the oviduct. Competitive approaches, such as experimental set-ups that test multiple males or semen samples simultaneously on the same tissue explants, are desirable because they reduce the likelihood of bias when using material from different females. Therefore, we established a fluorescent labelling technique that allows tagging and storage of spermatozoa before competitive studies of sperm–oviduct binding invitro. Fluorescent markers were tested for reliability and compatibility with parameters of boar spermatozoa viability. The addition of seminal plasma after density gradient centrifugation was essential to counteract centrifugation stress during the labelling procedure. It was demonstrated that sperm tagged with MitoTracker Green FM or MitoTracker Red FM can be successfully used in competitive sperm–oviduct binding studies. The assay was sensitive enough to indicate subtle effects of semen storage temperature on the ability of the spermatozoa to contribute to the female sperm reservoir.

Information extraction using neural language models for the case of online job listings analysis

In this article we discuss the approach to information extraction (IE) using neural language models. We provide a detailed overview of modern IE methods: both supervised and unsupervised. The proposed method allows to achieve a high quality solution to the problem of analyzing the relevant labor market requirements without the need for a time-consuming labelling procedure. In this experiment, professional standards act as a knowledge base of the labor domain. Comparing the descriptions of work actions and requirements from professional standards with the elements of job listings, we extract four entity types. The approach is based on the classification of vector representations of texts, generated using various neural language models: averaged word2vec, SIF-weighted averaged word2vec, TF-IDF-weighted averaged word2vec, paragraph2vec. Experimentally, the best quality was shown by the averaged word2vec (CBOW) model.

Impact assessment of mass gatherings using labelling procedure in ED, Nouvelle-Aquitaine, 2016

ObjectiveTo access the potential health impact on the population during mass gathering over time using labelling procedure in emergency department (ED).IntroductionThe massive flow of people to mass gathering events, such as festivals or sports events like EURO 2016, may increase public health risks. In the particular context of several terrorist attacks that took place in France in 2015, the French national Public Health agency has decided to strengthen the population health surveillance systems using the mandatory notification disease system and the French national syndromic surveillance SurSaUD®.The objectives in terms of health surveillance of mass gathering are: 1/ the timely detection of a health event (infectious cluster, environmental exposure, collective foodborne disease…) 2/ the health impact assessment of an unexpected event such as a terrorist attack.In collaboration with the Regional Emergency Observatory (ORU), a procedure for the labeling of emergencies has been tested to identify the ED records that could be considered as linked to the event.MethodsDuring summer 2016, the procedure was tested on seven major festive events throughout the region. In addition to the main medical diagnosis, a specific ICD-10 code “Y3388” was chosen to be used in associated diagnosis for records that were supposed to linked to the event.Information on the labeling procedure was insured by the ORU to the emergency departments.All records with medical diagnoses or medical pattern beginning by Y33 have been analyzed.ResultsNo significant increase in the global indicator was observed in the ED impacted by mass gathering. The ED labelling procedure identified 260 records: two thirds corresponded to young men and 17% came from abroad. Among the 250 records labeled in associated diagnosis, 39% were associated to traumatisms and 31% corresponded to alcohol intake.ConclusionsThis study shows that a labelling procedure allows the identification, quantification and characterization of the population ED records associated with mass gathering. Additionally, a labelling procedure to assess a potential impact of an event as mass gathering can be implemented fairly rapidly.